For a connection at the end of an optical fibre to cause a minimum amount of loss in light transmission the fibre must end in a plane surface perpendicular to its axis. Such an end can be obtained by various techniques such as swing, grinding and polishing which are difficult to perform in situ outside a laboratory. An end can also be obtained by a break started by a transversal score on the fibre in a zone where it has previously been stretched and bent. But this method, although more simple, is also difficult outside a laboratory, since it requires great accuracy in the tractive forces applied and in the radius of curvature imposed on the fibre as well as in the transversal stress which causes the scoring so that the break will not splinter or leave a lip which makes it unsuitable for forming a connection.
The present invention aims to provide a hand tool for cutting optical fibres which is easy to use in accordance with the above-mentioned method and provides the required accuracy.
It provides a hand tool for cutting an optical fibre comprising two articulated legs which have two free ends at the same distance from their pivot point, and referred to as the first ends, said ends being close together in a rest position and moving apart when the tool is operated.
Further, a support forming part for bending the optical fibre has a convex profile and is installed at the first end of one of the legs so that its convex surface is perpendicular to the plane of the two legs and faces away from the pivot point of these legs.
Two clips (one per arm) are installed on either side of the forming part in the extension of the convex profile thereof, each on the first end of the corresponding leg; said clips grinding the optical fibre on either side of the forming part.
A moveable knife is disposed on the first end of one of the legs, facing the convex profile of the forming part and extending thereacross.
First resilient means provided which tend to move the first ends of the two legs apart.
Second resilient means are provided which tend to bring the knife towards the forming part.
A setting mechanism moves the knife away from the forming part when the first ends of the two legs are moved towards each other.
A locking mechanism keeps the first ends of the two legs close together when they are in the rest position and keeps the knife away from the forming part and a double-action release mechanism, when the tool is operated, firstly releases the first resilient means progressively, then also releases the second resilient means progressively.
Other characteristics and advantages of the invention will become apparent from the accompanying claims and from the description hereinbelow of an embodiment given by way of an example.